Method of making patterns



(No Model 4 W. J. KEEP. METHOD OF MAKING PATTERNS.

Patented Oct. 15, 1889.

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. UNITED STATES PATENT OFFICE.

WILLIAM J. KEEP, OF DETROIT, MICHIGAN.

-METHOD OF MAKING PATTERNS.

SPECIFICATION forming part of Letters Patent No. 412,759, dated October 15, 1889.

Application filed October 23, 1888. $erial No. 288,970. (No model.)

T0 at whom it may concern.-

Be it known that I, WILLIAM J. KEEP, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Methods of Making Patterns, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement on my method of molding articles described in my application, Serial'No. 276,253, filed June 6, 1888; and the present invention consists, mainly, in the use of a non-metallic composition fusible at a low temperature for the backing of the copper film referred to in said application.

The common mode of producing fanciful or irregular-shaped patterns for castings is to.

first make a wood pattern-block by carving or otherwise, and from that produce a metal pattern, which has to be finished by filing and dressing at considerable expense. Attempts have been made to avoidthis expensive mode in the manner shown in the United States Patents Nos. 169,151 and 372,793; but neither of these shows a thin metallic shell stiffened with a composition of softer material. It has also been proposed to electroplate dentists molds, and then press into them either rubber, gutta-percha, or celluloid to form a dental plate in which the surface is united with the velectroplate on the molds; but in this case the lining is necessarily forced into the matrix by considerable pressure, as neither rubber, gutta-percha, nor celluloid can be poured into the molds, while by my method of construction the sti'ifening material-is poured into the mold between the patrix and matrix. In the ordinary process of electrotyping there is a film of copper strengthened by a backing of metal; but this process is not applicable to the making of patterns, for reasons hereinafter given.

In order to fully describe my method of operation, I will refer to the accompanying drawings, which show vertical central sections of the matrix, patrix, pattern, &c.

In the drawings, Figure 1 represents the original pattern-block and the matrix made therefrom, Fig. 2 represents the matrix prepared with a filling for forming the patrix. Fig. 3 represents the matrix, filling, and patrix. Fig. 4 represents the patrix and matrix without the filling. Fig. 5 represents the patrix and the matrix with the latter coated with the film. Fig. 6 represents the patrix and matrix with the film and backing. Fig. 7 represents a section of the complete pattern, and Fig. 8 represents the pattern mounted on the patrix for a follow-board.

In carrying out my invention I prefer to operate as follows: I first prepare a patternblock showing the face of the plate or what ever object it is desired to be cast, which pattern may be made by carving, modeling in clay, or'in any other convenient mode, and which is represented by a in Fig. 1. Upon this I cast a matrix of plaster-of-paris or other suitable material, which is represented by b. I next cover the part which is intended to give the face of the pattern with a filling c, Fig. 3,which should be of the thickness the pattern is intended to be. This filling maybe of putty, clay, or other soft plastic material, and should be put on in a series of narrow fiat strips set edge to edge, which may be laid easily into the matrix, and the strips united and smoothed by slight pressure. I may sometimes put on the filling with a brush, and do not intend to limit myself to any particular mode of making the same. When the lining has been properly done, I cast over it a patrix d.(see Fig. 3) of any suitable material, after which I remove the filling, so that when the patrix and matrix are placed in their proper relative positions there will be a space between them equal to the desired thickness of the pattern, as shown in Fig. 4. I then take the matrix and saturate it with paraffine and dust plumbago over its face, after which I set it in a copper solution, and

by the aid of a battery or otherwise electroplate the face of the matrix in amanner well understood and therefore unnecessary to describe here. When a film of sufficient tenaoity has been formed on the matrix, I place the patrix on top of the matrix and then pour V in the space between the film e and the patrix an easily-fusible composition to form a backing f for the film. This composition may be formed of a mixture of rosin and wax or paraffine, or any material that will melt easily and set firmly. When this is set and separated from the matrix and patrix, a plate or pattern such as is shown in section in Fig. 7 will be the result. \Vhen it is desired to use this plate as a pattern, it may be set upon the patrix as a follow-board, as shown in Fig. 8. I have drawn the film 6 very much exaggerated in thickness, so as to show it more distinctly. It need not, however, be anything near as thick as shown, as the backing forms the main strength of the pattern, and the merest film of copper will be sufficient.

In my aforesaid application, Serial No. 276,253, I have described a mode of making pattern-plates which is very similar to this except in the material used for the backing. That mode is successful with small plates; butwhen large plates are made, such as are frequently required for stoves, it is found to be impracticable,for the reasons given farther on. I may sometimes vary the process without departing from the spirit of my invention. For instance, I may, as the next step after making the matrix, elect-roplate the same, then line the electroplate with clay, &c.; next, make the patrix, then remove the patrix and lining, and, after replacing the patrix, pour an easilyfused composition between the patrix and the copper film. This is merely a variation in the procedure without any practical change in the result.

I deem the use of an easily-fusible composition for the backing to be very important, for the following reasons: It is practically im possible to make a pattern of a large plate with any backing-such as metal-which is very hot when poured, because, as the electro film is necessarily very thin, the least change of temperature expands the copper. As the matrix, being of plaster, cannot expand and the film is necessarily held rigid at the edges, the expansion by heat of the film would cause it to rise up from the matrix and buckle, and unfortunately it never comes back to its original form. This ruins the face of the pattern and causes the pattern to be of un-' even thickness. In the ordinary electrotype process the copper is first heated to the same temperature as the backing is to be and is held flat, face down, on an iron plate, and therefore metal can be easily used for the eleetrotyping. For my work the matrix cannot be heated at all, as it is full of paraffine, and the plaster would calcine. Owing to the great variety of the configurations of stove-plates, the use of metal plates to hold the film in the manner employed by electrotypers is of course impracticable. Even the resin and wax composition I use must have the lowest melting-point for these reasons.

Metal cannot be used for a backing on large plates without heating the matrix, because it would not run into a cold mold one-twelfth of an inch thick and as large as stove-founders require-say twenty-four inches by twentyfour inchesas the metal would chill too soon. Any material, as gutta-percha or celluloid, that would have to be laid on in a sheet and require pressing into the ornamental parts of the plate cannot be used, for it could not be made of a suifieiently even thickness to be used for stove-patterns, because to force it into the recesses of the plate the sheet would necessarily have to be stretched, and it would thus be much thinner in some places than in others. Besides this objection, the matrix and patrix, being'of plaster, would notstand the necessary pressure when made of the large size required in stove-plates, although they may and probably will stand for small plates for dental purposes.

In the course of my experience I have found that with very large plates the use of a composition of a low melting-point does not always prevent buckling, but this may be wholly overcome by giving the inside of the copper film a thin coating of the melted composition laid on with a brush after the manner of painting. Vhen the composition is poured into the space. between the film and the patrix, its heat is expended in meltin g the coat of the composition already on the film, and the plate does not therefore get heated sufficiently to buckle.

No claim is here made, broadly, to the feature of coating the film by painting it with the composition, as this is claimed in another application of even date herewith, Serial No. 288,971.

\Vhat I claim as new is- 1. The process herein described of making patterns, which consists in making a matrix and electroplating the face of the same, then placing a patrix over said matrix and pouring a non-metallic composition having a low melting-point into the space between the electroplate and the patrix, substantially as described.

2. The process herein described of making pat-terns, which consists in first preparing a pattern-block, then making a matrix from said block, then lining the interior of the matrix with material substantially of the thickness the desired article is to be cast, then making a patrix on the face of the lined matrix, next removing the lining, then electroplating the matrix, next replacing the patrix, and then pouring into the space between the patrix and metal plate a composition having a low meltingpoint, substantially as described.

3. The process herein described of making patterns, which consists in first making a matrix and electroplating the same, then painting the reverse side of the film with a material of 10W melting-point, then placing over the film a patrix, and then pouring into the space between the film and the patrix a. non-metallic material having a low meltingpoint, substantially as described.

In testimony whereof I affix my signature, in presence of two Witnesses, this 13th day of October, 1888/ WILLIAM J. KEEP.

Witnesses:

FRANK L. BR MLEY, ISAAC S. FILER. 

